From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay5-d.mail.gandi.net ([217.70.183.197]:50362 "EHLO relay5-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756585AbaDKJWC convert rfc822-to-8bit (ORCPT ); Fri, 11 Apr 2014 05:22:02 -0400 Received: from mfilter29-d.gandi.net (mfilter29-d.gandi.net [217.70.178.160]) by relay5-d.mail.gandi.net (Postfix) with ESMTP id 85EA041C064 for ; Fri, 11 Apr 2014 11:22:00 +0200 (CEST) Received: from relay5-d.mail.gandi.net ([217.70.183.197]) by mfilter29-d.gandi.net (mfilter29-d.gandi.net [10.0.15.180]) (amavisd-new, port 10024) with ESMTP id QjUzYIXG7Aqe for ; Fri, 11 Apr 2014 11:21:59 +0200 (CEST) Received: from zafu.localnet (dhcp230.cr2i.univ-montp2.fr [162.38.105.230]) (Authenticated sender: michel@bouissou.net) by relay5-d.mail.gandi.net (Postfix) with ESMTPSA id 7EFE241C091 for ; Fri, 11 Apr 2014 11:21:57 +0200 (CEST) From: =?ISO-8859-1?Q?Sw=E2mi?= Petaramesh To: linux-btrfs@vger.kernel.org Subject: mount options ignored / unclear Date: Fri, 11 Apr 2014 11:21:55 +0200 Message-ID: <1988570.7Waz7R0erI@zafu> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hello, (Still in my quest for BTRFS performance) It is extremely unclear which BTRFS mount options are "filesystem wide" and will apply to each and every mountpoint in the BTRFS filesystem, and which options can be set per subvolume or per mountpoint. As far as I can tell, there is no reliable documentation about this, is there any ? (Kernel is 3.13, Fedora) i.e. I have in fstab : /dev/sda3 / btrfs subvol=FEDORA,noatime,compress=lzo,autodefrag ...So without suprise I get in /proc/self/mountinfo: 36 1 0:32 /FEDORA / rw,noatime shared:1 - btrfs /dev/sda3 rw,seclabel,compress=lzo,space_cache,autodefrag ...But then I have in fstab: /dev/sda3 /home/me/.cache btrfs subvol=/NOCOW/me/.cache,nodatacow,compress=no,noatime So it is with great suprise the I get in /proc/self/mountinfo: 49 47 0:32 /NOCOW/me/.cache /home/me/.cache rw,noatime shared:33 - btrfs /dev/sda3 rw,seclabel,compress=lzo,space_cache,autodefrag ...I'm not suprised to see "space_cache" which I would assume to be FS-wide, but what the hell does "autodefrag" do in there, or even worse "compress=lzo", where "compress=no" has been exlicitely specified in fstab ? That's a bug, as far as I can tell. Kind regards. -- Swâmi Petaramesh http://petaramesh.org PGP 9076E32E